Powder Coating with a Fluidized Bed

There’s no beating the beauty and durability of a high-quality powder-coated part. There’s just something about the look and feel of the finish that goes far beyond mere painting and makes it worth the effort and expense. The typical electrostatic spray powder-coatingĀ setup can be expensive, though, and not necessarily suitable for every workpiece.

Enter the fluidized-bed powder coating chamber, perfect for limited runs of small parts, and the brainchild of [Andrew Mayhall]. With a business providing furniture kits based on iron pipe, [Andrew] needed a way to finish flanges and fittings, and powder coating provided the best look. The fluidizer he built is a great alternative to spray coating; it blows air through a bed of fine thermoplastic granules, which causes them to act like a fluid. It’s similar to the fluidized-bed hot tub we recently featured, but on a much smaller scale and with different requirements based on the ultrafine particle size and aggregation properties of the powder. [Andrew] had to add mechanical agitation to achieve a homogeneous fluid bed, and after much experimentation he’s now able to dip preheated parts into the bed and achieve one-step powder coating. The video after the break shows some of the operational details.

Does electrostatic powder-coating sound like more of your thing? No problem – DIY solutions abound, and a homebrew oven to bake your parts may be as close as the nearest file cabinet.

Continue reading “Powder Coating with a Fluidized Bed”

Fill Your Hot Tub With Sand. For Science!

Here at Hackaday, we can understand if you don’t like sand. It’s coarse, rough and irritating, and it gets everywhere. With that said, [Mark Rober] discovered a great way to have fun with sand right in your own back garden.

We’ll preface this by stating that this isn’t the easiest hack to pull off on a lazy Saturday afternoon. You need a spare hot tub, plenty of pipe, and a seriously big air supply. But if you can pull it all together, the payoff is fantastic.

What [Mark] has achieved is turning a regular hot tub into a fluidized bed. In simple terms, this is where a solid particulate material (like sand) is made to act more like a fluid by passing pressurized fluid through the material. Through a carefully built series of drilled copper pipes, [Mark] manages to turn the hot tub into a fluidized bed, much to the enjoyment of his young nephews.

While it’s not the easiest hack to copy at home, [Mark] drives home the science of both the fluidized bed and why certain objects float or sink in the sand. It’s something that can also be easily tackled at a smaller scale, if you’re looking for something more achievable for the average maker.

For more sand science, how about using it to hold up your car?

[Thanks to Keith for the tip!]